The present disclosure discloses a method of transmitting a signal, a wearable communication device and a terminal device. The method includes: receiving, by a wearable communication device, a modulated wave signal transmitted by a terminal device; demodulating the modulated wave signal to obtain a to-be-decoded signal; performing a waveform shaping process on the to-be-decoded signal to obtain a square wave signal, where a high level in the square wave signal is configured to represent a first preset value, and a time interval is existed between two high levels corresponding to any two adjacent first preset values; acquiring time interval eigenvalues in the square wave signal; acquiring a one-to-one mapping relation of the interval eigenvalues and a plurality of coding sequences; and performing, according to the time interval eigenvalues and the mapping relation, a first decoding process and a second decoding process on the square wave signal to obtain original data.

A receiver and method for a wireless signal transmission system use digital amplitude modulation of a base band signal having a symbol clock frequency. The receiver includes a reference generator which generates a local reference frequency, a mixer to extract the base band signal, a high pass filter to suppress a DC component, an amplifier, an analog-to-digital converter and a digital signal processor to receive digital signals and extract symbols. A base band signal rotation detection circuit detects rotation of the base band signal upstream of the high pass filter. The digital signal processor determines a symbol clock phase by generating a coarse estimate of the symbol clock phase and correcting the coarse estimate based on detected rotations of the base band signal. A determination that the symbol clock phase corresponds to a complete rotation is used in relation to the extraction of symbols.

The optical receiving device with phase compensation apparatus uses coherent opto-electric conversion and is designed for receiving phase- or quadrature-amplitude-modulated optical signals. The phase compensation apparatus includes following elements: a carrier-phase estimation unit that estimates carrier phase errors in a received symbol string; a gain adjustment unit that adjusts weighting of each symbols in phase error evaluation performed in the carrier-phase adjustment unit; a phase-cycle-slip reduction unit with a phase-cycle-slip detector using statistical processing performed on the output symbols from the carrier-phase estimation unit; and a phase compensation circuit that compensates carrier phase errors of the received signal using an output from the carrier phase estimation unit.

A method is provided for processing broadcast data in a broadcast transmitter. Broadcast service data is randomized. The randomized broadcast service data is first-encoded to add parity data to the randomized broadcast service data. The first-encoded broadcast service data is second-encoded. The second-encoded broadcast service data is first interleaved. The first-interleaved broadcast service data is second-interleaved. Signaling data is encoded for signaling the broadcast service data. The encoded signaling data is third-interleaved. The third-interleaved signaling data is fourth interleaved. A frame is transmitted that is divided into a data region including the second-interleaved broadcast service data, a first signaling region including the fourth-interleaved signaling data and a second signaling region that includes at least one symbol that is used for synchronization and channel estimation. The frame includes known data. The encoded signaling data includes information for identifying the code rate and information related to the known data.

A wireless communications system is configured to perform wireless communication by using a first band dedicated to the system and a second band shared by the system and another wireless communications system. The system includes a base station configured to transmit in the first band to a terminal when detecting an available carrier wave of the second band, a control signal permitting data transmission in the second band from the terminal to the base station, the base station continuously sending out a radio wave of the second band during a period until the data transmission; and the terminal configured to perform the data transmission after a predetermined time from transmission of the control signal by the base station.

A measurement apparatus, for example a digital oscilloscope, receives an amplitude modulated (AM) signal comprising a baseband signal, having a baseband waveform, modulating a carrier signal, and reconstructs the baseband waveform. The measurement apparatus: samples the AM signal at a sampling rate which produces a plurality of data samples for each period of the carrier signal; determines the amplitude of the baseband signal for each of a plurality of periods of the carrier signal from at least some of the plurality of data samples for each period; and reconstructs the baseband waveform from the amplitudes of the baseband signal for each of the plurality of periods of the carrier signal. The measurement apparatus may display the reconstructed baseband waveform on a display device.

A measurement apparatus, for example a digital oscilloscope, receives an amplitude modulated (AM) signal comprising a baseband signal, having a baseband waveform, modulating a carrier signal, and reconstructs the baseband waveform. The measurement apparatus: samples the AM signal at a sampling rate which produces a plurality of data samples for each period of the carrier signal; determines the amplitude of the baseband signal for each of a plurality of periods of the carrier signal from at least some of the plurality of data samples for each period; and reconstructs the baseband waveform from the amplitudes of the baseband signal for each of the plurality of periods of the carrier signal. The measurement apparatus may display the reconstructed baseband waveform on a display device.

Certain aspects of the present disclosure provide techniques for multi-carrier on-off keying communications. A method for wireless communications by an apparatus includes receiving a signal comprising multiple carrier frequencies modulated with on-off keying; decoding the signal based at least in part on a delta frequency being associated with a first carrier frequency and a second carrier frequency among the multiple carrier frequencies; and recovering data from the decoded signal.

Certain aspects of the present disclosure provide techniques for multi-carrier on-off keying communications. A method for wireless communications by an apparatus includes receiving a signal comprising multiple carrier frequencies modulated with on-off keying; decoding the signal based at least in part on a delta frequency being associated with a first carrier frequency and a second carrier frequency among the multiple carrier frequencies; and recovering data from the decoded signal.

A digital calibration device for an RF-system includes a first input to receive I-channel data and a second input to receive Q-channel data; a first filter coupled to the first input and configured to estimate a DC offset of the I-channel data and to subtract the DC offset from the I-channel data to provide filtered I-channel data; and a second filter coupled to the second input and configured to estimate a DC offset of the Q-channel data and to subtract the DC offset from the Q-channel data to provide filtered Q-channel data. The device includes a combining element configured to provide a specified magnitude value (adc_data_iq) based on the filtered I- and Q-channel data; and a level detector configured to receive the magnitude value of the filtered I-channel data and Q-channel data and to provide a filter coefficient for the first and second filters depending on the magnitude value.